Traffic-related activities driven dust-bound magnetic pollution in urban road-system: Case study of Xiamen island, China

Abstract

Sources of magnetic phases in urban dust include traffic-related activities, industrial products and detrital minerals. Exposure to magnetic phases in urban dust co-associated with trace metals is associated with respiratory ailments in sensitive organisms. Here, we collected samples of surface roadside dust and topsoil from Xiamen island, Fujian, China and then magnetic properties were determined using rock-magnetic methods. Magnetic particle concentrations in surface roadside dust was found to be significantly high compared with magnetic content in topsoil using magnetic susceptibility (𝜒LF), saturation isothermal remanent magnetization (SIRM) and susceptibility of anhysteretic remanent magnetization (𝜒ARM). Roadside dusts had much lower percent frequency-dependent susceptibility (1.83 ± 0.12%) than topsoil (2.96 ± 0.14%). Given the 𝜒ARM/SIRM vs 𝜒fd% and first-order reversal curves, most of the magnetic particles in roadside dust were large than in topsoil. Variable temperature dependence of magnetization, isothermal remanent magnetization decomposition spectra and first-order reversal curves suggested the enhancement of dust 𝜒LF, SIRM and 𝜒ARM were related to the exogenous pseudo-single-domain magnetite-like materials. This study provides a better understanding of magnetic ageing of dust particles in coastal cities. These results will be useful in optimizing environmental policies aimed at regulating magnetic dust particles pollution in coastal cities.